scholarly journals Thermal and pressure ionization in warm, dense MgSiO3 studied with first-principles computer simulations

2020 ◽  
Author(s):  
Felipe González-Cataldo ◽  
Burkhard Militzer
Keyword(s):  
Computer Simulations ◽  
First Principles

scholarly journals Equation of state of hot, dense magnesium derived with first-principles computer simulations

2020 ◽  
Vol 27 (9) ◽  
pp. 092706 ◽  
Author(s):  
Felipe González-Cataldo ◽  
François Soubiran ◽  
Burkhard Militzer
Keyword(s):  
Equation Of State ◽  
Computer Simulations ◽  
First Principles

Modelling Damping in Computer Simulations: Is All Damping Viscous?

2011 ◽  
Author(s):  
Hugh Goyder
Keyword(s):  
Computer Simulations ◽  
First Principles ◽  
Damping Force ◽  
Lagrange’S Equation ◽  
Starting Point ◽  
Air Resistance ◽  
Viscoelastic Effects ◽  
Dissipation Model ◽  
Dynamic Components ◽  
Damping Model

The standard damping model is the viscous dashpot for which the damping force is proportional to velocity. However, this simple model seems not to reflect real conditions where there may be viscoelastic effects, friction or air resistance. No general models for damping are available that can be developed from first principles and used in computer simulations. To help with this difficulty the fundamental theory that should underpin any general damping model is assembled here. The only available formulation for damping in mechanics is the Rayleigh dissipation model that can be used with Lagrange’s equation. This model is strictly viscous and linear. The possibility of using this model for all damping circumstances is examined. A starting point for the development of a theory is the need for causality. This need is used to formulate the concept of a pure dashpot (i.e. not mixed with other dynamic components) which is shown to be viscous. Furthermore in order to represent damping in general it is necessary to embed the viscous dashpot with other mechanical components which are not dissipative and are either linear or nonlinear. It appears that even for non-linear systems the only form of damper that is possible is the linear viscous dashpot.

scholarly journals Nonideal mixing effects in warm dense matter studied with first-principles computer simulations

2020 ◽  
Vol 153 (18) ◽  
pp. 184101
Author(s):  
Burkhard Militzer ◽  
Felipe González-Cataldo ◽  
Shuai Zhang ◽  
Heather D. Whitley ◽  
Damian C. Swift ◽  
...  
Keyword(s):  
Computer Simulations ◽  
First Principles ◽  
Dense Matter ◽  
Warm Dense Matter ◽  
Mixing Effects

Structural properties of amorphous aluminum and aluminum-nitrogen alloys. Computer simulations

2004 ◽  
Vol 848 ◽  
Author(s):  
Ariel A. Valladares ◽  
Alexander Valladares ◽  
R. M. Valladares ◽  
A. Calles
Keyword(s):  
Physical Properties ◽  
Computer Simulations ◽  
First Principles ◽  
Hard Sphere ◽  
Distribution Functions ◽  
Radial Distribution Functions ◽  
Semiconducting Materials ◽  
Atomic Structures ◽  
Lennard Jones ◽  
Nitrogen Alloy

AbstractLiquid and amorphous metallic systems have proven difficult to model. Some efforts have relied on the use of parameterized classical potentials of the Lennard-Jones type or geometric hard sphere simulations, but first principles approaches have been rarely used. Clearly a knowledge of atomic structures is paramount for calculating physical properties. In this work we apply our recently developed ab initio DFT approach (A. A. Valladares et al., Eur. Phys. J. 22 (2001) 443) for the generation of amorphous semiconducting materials, to amorphize aluminum and an aluminum-nitrogen alloy. We report radial distribution functions (RDFs) and specific atomic structures of periodic amorphous/liquid cubic supercells of 108 atoms with a volume of (12.1485 Å)3, generated using the Harris functional.

scholarly journals Influence of Oxygen Vacancies in Gas Sensors Based on Tin Dioxide Nanostructure: A First Principles Study

Proceedings ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 14
Author(s):  
Soufiane Krik ◽  
Andrea Gaiardo ◽  
Matteo Valt ◽  
Barbara Fabbri ◽  
Cesare Malagù ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Gas Sensors ◽  
First Principles ◽  
Oxygen Vacancies ◽  
Tin Dioxide ◽  
First Principles Study ◽  
Performance Predictions

The use of computer simulations for performance predictions has become almost essential.[...]

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